Automatic leveling ladder



March 1, 1938.

W. A. WARREN ET AL.

AUTOMATIC LEVELING LADDER Filed Feb 16, 1935 INVENTOAS VV/Y/fdm A.Warren and C/aude E. Bowers Patented Mar. 1, 1938 UNITED STATESAUTOMATIC LEVELING LADDER William A. Warren, Long Beach, and Claude E.Bowers, Los Angeles, Calif.

Application February 16, 1935, Serial No. 6,858

cally shift to conform to uneven surfaces upon which the ladder may bepositioned while the steps of the ladder remain substantially horizontalor level, and the objects of our invention are:

First, to provide a ladder of this class which is strong and durable andin which the legs of the ladder will automatically shiftto accommodatethe ladder to uneven surfaces upon which it may be positioned;

Second, to provide a ladder of this class in which the weight of theperson stepping on the ladder will automatically shift the legs of theladder while the main portion of the ladder will remain substantiallystationary;

Third, to provide a ladder of this class with means for rigidly securingthe legs in varying relation to each other;

Fourth, to provide a ladder of this class with means for providingfrictional relation between the shiftable legs and the main legs of theladder so that the legs shift only when weight is brought to bear on thesteps of the ladder;

1.) Fifth, to provide reinforcing means for the lower end of the ladder;

Sixth, to provide an automatic shifting means for the legs of a ladderof thisclass which is applicable to the ordinary standard two-legladder,

30 to the step-ladder, and also to the tripod ladder;

and

Seventh, to provide a ladder of this class which is very simple andeconomical of construction, automatic in its action, durable andefiicient.

5 With these and other objects in view as will appear hereinafter, ourinvention consists of certain novel features of construction,combination and arrangement of parts and portions as will be hereinafterdescribed in detail and particularly set forth in the appended claims,reference being had to the accompanying drawing and to the characters ofreference thereon which form a part of this application, in which:

Figure 1 is a rear elevational view of our ladder With the legssubstantially positioned on a level surface; Fig. 2 a side edge viewthereof; Fig. 3 a view similar to Fig. 1 showing one of the legselevated and the adjusted relation of the other parts of the laddersubstantially level with the 50 steps substantially horizontal; Fig. 4is an enlarged sectional View from the line 44 of Fig. 1; Fig. 5 afragmentary sectional view on an enlarged scale from the line 5-5 ofFig. 1, and Fig. 6 a further enlarged fragmentary sectional view fromthe line 6-6 of Fig. 1.

similar characters of reference refer to similar parts and portionsthroughout the several views of the drawing.

The leg members I and 2, steps 3, equalizing stationary bar 4,equalizing shiftable bars 5 and; 5 6, shiftable leg members I and 8,spring clamps 9, clamp bolts I0, and wing nuts II, constitute theprincipal parts and portions of our ladder.

The legs I and 2 and steps 3 are of the conventional form and securedin; rigid relation to. each other in conventional manner. Shiftablymounted longitudinally with the leg member I is a metallic shiftable legmember I, and shiftably mounted longitudinally with the leg member 2 isa metallic shiftable leg member 8. These leg.l5 members I and 8 consistof front strip portions la and 8a and rear strip portions 1b and 8bwhich are substantially the same width as the leg members I and 2, andthe front and rear strip members are integrally connected at their lowerends with pocket members To and 86 which are adapted to receive thelower ends of the ladder legs I and 2 and in which these lower endsreciprocate with the automatic shifting of the shiftable leg memberswith the stationary leg members. These '25 pockets are provided on thelower ends. of the strips Ia and lb and 8a and 8b to prevent dirt andother matter gathering or getting into the lower end preventing thelongitudinal shifting of these leg members I and 8 relative to themembers I and 2.

Secured between the legs I and 2 and extending across intermediate thefront and rear sides of these leg members I and 2 is an equalizingstationary bar 4 which is secured to the inner side of the leg members Iand 2, as shown best in Figs. 4 and 5, and pivotally mounted on oppositesides of this member 4 are shiftable bars 5 and'6 by means of a rivetmember 4a, and these members 5 and 6 are pivotally connected at theiropposite ends with the shiftable leg members I and 8, as shown best inFigs. 4 and 6 of the drawing, preferably by rivet connections. Thus themembers I and 8 may be shifted, the one upwardly, the other downwardly,upon the pivotal mounting 4a, it being noted that these members shiftoutwardly and inwardly because of the radial movement of the members 5and 6.

The upper ends of the members 1b and 8b are provided with slots Id and8d at their upper ends to permit the longitudinal shifting, and throughthese slots are provided bolts I0 which extend through the legs I and 2of the ladder and there is provided a spring clamp member 9 which isadapted to rest against the upper ends of these strips 1b and 8b andform a friction clamp for clamping the upper ends of these membersagainst the leg members I and 2 and this friction is adjusted by meansof wing nuts I I on the bolts In.

The operation of the ladder is as follows: The ladder is positioned onthe ground with the shiftable leg portions 10 and positioned on unevensurfaces. Then with a person stepping on the steps 3 of the ladder therigid portion of the ladder consisting of the leg members I and 2 andsteps 3, will move downwardly and the shiftable leg members 1 and 3 willautomatically assume relative positions, as shown in Fig. 3 of thedrawing, while the step members 3 remain substantially horizontal, andif desired these leg members I and 8 may be clamped by use of the wingnuts I l on the bolts it, thus holding them in that certain relativeposition.

It will be noted that the equalizing bars shift with the members I and8.

Though we have shown and described a particular construction,combination and arrangement of parts and portions, we do not wish to belimited to this particular construction, combination and arrangement,but desire to include in the scope of our invention the construction,combination and arrangement substantially as set forth in the appendedclaims.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. In a ladder, a pair of leg members, a plurality of steps rigidlysecured thereto spacing said leg members in rigid relation, othershiftable leg members including spaced strip portions extendinglongitudinally on the front and back side of each of said leg membersand shiftable longitudinally thereof and including a main pocket portionextending below the lower ends thereof, means for equalizing theshifting of said shiftable leg members, said means for equalizingincluding a single stationary bar rigidly supported at its ends on saidfirst mentioned leg members, and a pair of shiftable bars pivotallysupported intermediate said first mentioned leg members on saidstationary bar and pivotally connected with said last mentioned legmembers at the front and back sides of said first mentioned leg members.

2. In a ladder, a pair of leg members, a plurality of steps rigidlysecured thereto spacing said leg members in rigid relation, othershiftable leg members including spaced strip portions extendinglongitudinally on the front and back side of each of said leg membersand shiftable longitudinally thereof and including a main pocket portionextending below the lower ends thereof, means for equalizing theshifting of said shiftable leg members, said means for equalizingincluding a single stationary bar rigidly supported shiftable at itsends on said first mentioned leg members, and a pair of shiftable barspivotally supported intermediate said first mentioned leg members onsaid stationary bar and pivotally connected with said last mentioned legmembers at the front and back sides of said first mentioned leg members,and means for frictionally supporting said shiftable leg membersrelative to the first mentioned leg members.

3. In a ladder, a pair of leg members, a plurality of steps rigidlysecured thereto spacing said leg members in rigid relation, othershiftable leg members including spaced strip portions extendinglongitudinally on the front and back side of each of said leg membersand shiftable longitudinally thereof and including a. main pocketportion extending below the lower ends thereof, means for equalizing theshifting of said shiftable leg members, said means for equalizingincluding a single stationary bar rigidly supported at its ends on saidfirst mentioned leg members, and a pair of shiftable bars pivotallysupported intermediate said first mentioned leg members on saidstationary bar and pivotally connected with said last mentioned legmembers at the front and back sides of said first mentioned leg members,means for frictionally supporting said shiftable leg members relative tothe first mentioned leg members, said means including clamp meansadapted to provide rigid connection between said shiftable leg membersand said first mentioned leg members.

4. In a ladder, a pair of leg members, a plurality of steps rigidlysecured thereto spacing said leg members in rigid relation, othershiftable leg members including spaced strip portions extendinglongitudinally on the front and back side of each of said leg membersand shiftable longitudinally thereof and including a main pocket portionextending below the lower ends thereof, means for equalizing theshifting of said shiftable leg members, said means for equalizingincluding a single stationary bar rigidly supported at its ends on saidfirst mentioned leg members, and a pair of shiftable bars. pivotallysupported intermediate said first mentioned leg members on saidstationary bar and pivotally connected with said last mentioned legmembers at the front and back sides of said first mentioned leg members,means for frictionally supporting said shiftable leg members relative tothe first mentioned leg members, whereby when one shiftable leg membermoves in one direction, the other moves in the opposite direction andthe pocket means at the extended ends of each of said shiftable legmembers in which the lower ends of said first mentioned leg members areshiftably mounted.

WILLIAM A. WARREN. CLAUDE E. BOWERS.

